stockwell



(No Model.) 2 Sheets-Sheet 1.

L. W. STOCKWELL.

SWITCH FOR ELECTRIC MOTOR AND OTHER CIRCUITS.

No. 326,603. Patented Sept. 22, 1885.

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2 Sheets-Sheet 2.

(No Model.)

L. W. STOCKWELL.

SWITCH FOR ELECTRIC MOTOR AND OTHER CIRCUITS.

,,, Patented Sept. 22, 1885.

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UNITED STATES LEVI V. STOCKWVELL, OF CLEVELAND,

PATENT OFFICE.

OHIO, ASSIGNOR TO THE CLEVELAND ELECTRIC MOTOR COMPANY, OF SAME PLACE.

SPECIFICATION forming part of Letters Patent No. 326,603, dated September 22, 1885.

Application filed June 4, 1884. (No model.)

To all whom it may concern:

Beit known that I, Lnvr W. STOCKWELL, of Cleveland. in the county of Cuyahoga, in the State of Ohio, have invented certain new and useful Improvements in Switches for Motor and other Circuits, of which the following is a specification. I

My improved boards are especially designed for-use in the circuits of dynamo-electric ma- 1o chines containing electric motors, lamps, or i other appliances, or a combination of them.

The object of the invention is to maintain a uniform resistance in a line at each motor,

I5 stan't, whether the motor is running or is at rest. r In the accompanying drawings, Figure l is a plan View of the face of the board. Fig. 2is merely a view of the bottoni plate or under side of the switch-box. Fig. 3 is a plan view i with the under plate of the switch-box re- I moved. Fig.4 is an interior plan view ofthe supplemental resistance-bars. Fig. 5 is adii agram illustrating-the connections and circuits. Fig. 6 is a vertical longitudinal section on the line 6 6 of Fig. 1, and Fig. 7 is a transverse section showing merely the two sets of resistance-bars.

Referring for the present solely to the dia- I gram view, Fig. 5, the main line L enters the instrument at the binding-p0st A. which is in electrical connection with a plate, a, which isin electrical communication with another binding-post, A, and with a contactliutton, 5 A. The main resistance R is connected at i this side of the instrument directly with the I post A,with which themain line is connected, i and the opposite side of the resistance It is connected with a post, B, through which the I 40 main line L leaves the instrument. This post B is in contact with a plate, I), which is I also in electrical connection with a binding I post, B, and a contact, B the arrangement i being the same on both sides of the instru- I 5 ment. The resistance R is composed of a series of resistancebars, 1', preferably of carbon, which are connected in the ordinary way, I as clearly illustrated in the figure. From the post A a line, 8, runs through a-supplementary 5o resistance, S, also composed of connected rcsistance-bars, preferably of carbon, and from so that the electro-motive force will be conthence the line 8 runs to the heel of a pivoted switch-finger, l), and from thence by line m. through a motor, M, or other appliance, to the bindingmst B on the plate I). The resistance-bars r are connected, as shown, in a continuous series, and on the side next to the switchfinger D the loop of wire connecting the ends of each pair of bars is electrically connected with one of a series of contacts. 0 to which are traversed by the finger D. The current which enters the instrument at A, will of course divide inversely, according to the resistance of the loop-circuits through the resistance S and the resistance It. \Vith the contact-finger in the position shown in the diagram-that is, on the contact ca part of the current entering at A would pass through S and part would enter the resistance R. The current entering the resistance B, after passing through the first four resistance-bars 0'. would unite with the current passing through the resistance S at the switch-finger D, and the current would then pass through the motor M and through the remaining bars of the resistance It, according to the relative resistance of the two paths. The current which passes through the remaining resistance-bars of the-resistance R to the binding-post B would there unite with the current which had passed through the motor M, and go to line L. If the switclrlinger I.) be moved from the contact 0, so as to rest on the contact A the main course of the current would be directly through the finger D and motor to the line L. No current would pass through the resistance S and little or no current through the resistance lt; but if the switch-finger D be moved toward 1?, at each succeeding contact in its course the current passing directly 0 through the motor M will be reduced, and there will be more current through the resistance S. As before remarked, the currents which unite at the finger D will pass through the motor and through the remaining resistancebars of the resistance It, according to their relative resistances, and as the finger l) is moved toward the contact B the number of resistance-bars in the branch of the circuit through the finger l) and B would be (10- I00 creased, and a relatively greater current would pass through said bars to the bindingpost B,

thus reducing the amount of current passing through themotor. If the movement of the finger D be continued until it reaches the con tact B as shown by the dotted lines in the diagram, the current will cease to pass through the motor M, but will pass through It and S proportionately to their resistances. The resistance of S should be the same as that of the motor M, and the resistance of B should be so proportioned that when the finger D is on the contact A the motor will run with the great est power desired. The sections 1. 2 3 l 5 6 7 8 of the resistance B have each the same resistanee as the motor. \Vhen the finger D is on the contact N, then eight parts of the current will pass through the motor M and one part through the resistance It; but if the finger 1) rests on the contact 0 half the current will pass through section 8 of the resistance R and the other half through the motor M. When the switch-finger rests on the contact 13 as shown in dotted lines, eight parts of the current received at A will pass through the resistance S and one part through the resistance R, cutting the motor entirely out. \Vhatever may be the position of the finger D, therefore, the internal resistance of the instrument and the amount of current leaving it at the post 13 are the same. The motor or other appliance may therefore be started, stopped, and run without creating variations of electromotive force in the circuit. As before remarked, the electrical resistance of S M and the sections 1 to 8 of the main resistance R are equal, and I have in the drawings indicated this by marking each of them 10.

Fig. 1 represents the face of the switchboard, and shows the finger D drawn normally over to the contact B by spring d. In this position the motor is cut out of circuit, as described. By means of a cord or other suitable device, d, which may be actuated and held in position by a foot-lever or any other desirable means, the lever may be drawn against the force of the spring over the contact-buttons to throw the motor into operation and vary the power with which it may be driven. The different wires shown in Fig. 1 are lettered to correspond with th ose in the diagram, and the connections will be plain.

The main resistance It is preferably arranged in an iron case, which is perforated, as indicated in Figs. 1 and 2, to permit the free circulation of air. The supplemental resistance ois mounted in a supplemental boX or case, (shown in Figs. 4, 6, and 7,) which is bolted to the under side of the main switchbox.

The carbon bars are provided with metal sockets e at their ends, and with metal fingers e projecting from these sockets, by means of which the bars are mounted on cross-piecesF in the case, which cross-pieces are made of vwood or other suitable insulating material.

The bars are held in place by staples, which are driven down over thc'lingers c. The bars are electrically connected alternately at opposite ends with the following bars in the series. This is preferably done by small plates 0 which may be screwed to the socketpieces 0. This construction is clearly illustrated in Fig. 3.

The arrangement of the bars in both the main resistance R and the supplemental resistance Sis substantially the same. In the supplemental resistance, however, as shown in Fig. 4, single socket-pieces e are provided. for the reception of the ends of the adjoining bars. This manner of connecting resistance bars, however, is of course well understood, and it is well known the current enters a bar at one end and is caused to traverse succcs sively through all the bars in the series.

The metal sockets or end pieces, c, may be electroplated on the ends of the bars, if desired.

The boxing or casing G of the main resistance It is formed of two sections, which are bolted together. The resistance-board thus constructed may be secured in the desired position in any suitable well-known way.

Eight pairs of bars only are shown in the diagram, Fig. 5, while ten are shown in Fi 3, and in the latter figure one pair of bars on each side of the series is unconnected directly with any contact swept by the finger D. This latter construction of course causes a greater change in the relative resistance of the branch circuits at those two points. WVhere ten pairs of bars are used, as in Fig. 3, an additional contact for each bar may be placed in the series 0 and O; or the additional pairs of bars may be omitted.

I prefer to construct the instrument in accordance with the diagram View, Fig. 5that is, with each pair of bars connected with a contact, as shown.

I claim as my invention- 1. The combination, substantially as set forth, of a main line, aresistanee, S, an electromotor or other instrument, devices, as described, for varying the resistance of the branches of the circuit, and the resistance R, which is connected up in sections, as de scribed, the resistance of each of said sections and of the supplemental resistance S being equal to that of the motor or other instrument.

2. The combination of the main resistance It, the contacts 0 to a, connected with the sections thereof, the lever which traverses them, the conducting-plates a Z) on each side of said resistance, the binding-posts A A and B B, and the contacts A B on said plates, the motor, the supplementary resistance, and circuits and connections, as set forth.

In testimony whereof I have hereunto subscribed my name.

LEVI \V. STOCIUVELTJ.

\Vitnesses:

H. CLARK FORD,

L. S. Frsrr. 

